Browsing by Author "Spagnuolo, Michela"

Now showing 1 - 8 of 8
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    Comparison and Integration of Erosion Evaluation Methods for Rheumatic Degenerative Diseases
    (The Eurographics Association, 2020) Paccini, Martina; Patanè, Giuseppe; Spagnuolo, Michela; Biasotti, Silvia and Pintus, Ruggero and Berretti, Stefano
    Monitoring the development of degenerative rheumatic diseases is at the core of an efficient medical evaluation of the patient. Acquiring information on the pathology progression, indeed, helps to personalize the therapy in order to slow the pathology degeneration. Follow-up exams allow medical doctors to evaluate the situation of the patient over time. Through medical imaging scans, these exams help to identify erosion processes, which are typical indicators of a rheumatic illness. The paper presents a comparison between different methods aiming to identify erosion sites in follow-up exams. In particular, geometricbased and texture-based approaches are compared in terms of extracted information and achieved results. Finally, these two approaches are integrated in order to achieve a more complete analysis of the input anatomical district and of the underlying pathology.
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    Feature-based Characterisation of Patient-specific 3D Anatomical Models
    (The Eurographics Association, 2019) Banerjee, Imon; Paccini, Martina; Ferrari, Enrico; CATALANO, CHIARA EVA; Biasotti, Silvia; Spagnuolo, Michela; Agus, Marco and Corsini, Massimiliano and Pintus, Ruggero
    This paper aims to examine the potential of 3D shape analysis integrated to machine learning techniques in supporting medical investigation. In particular, we introduce an approach specially designed for the characterisation of anatomical landmarks on patient-specific 3D carpal bone models represented as triangular meshes. Furthermore, to identify functional articulation regions, two novel district-based properties are defined. The performance of both state of the art and novel features has been evaluated in a machine learning setting to identify a set of significant anatomical landmarks on patient data. Experiments have been performed on a carpal dataset of 56 patient-specific 3D models that are segmented from T1 weighed magnetic resonance (MR) scans of healthy male subjects. Despite the typical large inter-patient shape variation within the training samples, our framework has achieved promising results.
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    A First Step Towards Cage-based Deformation in Virtual Reality
    (The Eurographics Association, 2020) Scalas, Andreas; Zhu, Yuanju; Giannini, Franca; Lou, Ruding; Lupinetti, Katia; Monti, Marina; Mortara, Michela; Spagnuolo, Michela; Biasotti, Silvia and Pintus, Ruggero and Berretti, Stefano
    The advent of low cost technologies makes the use of immersive virtual environments more interesting for several application contexts. 3D models are largely used in such environments for providing feelings of immersion and presence in the virtual world. 3D models are normally defined in dedicated authoring tools and then adapted to be used in the virtual environments; thus, any change in the model requires to loop back to the authoring tool for performing the wished modification and the successive adaptation processes. The availability of shape modification capabilities within the virtual environment can avoid the above modification-adaptation loop. To this aim, we present our first step in the development of a 3D modelling system in Virtual Reality. The shape modification is achieved through a cage-based deformation approach, applied to semantically enriched meshes, carrying annotated meaningful regions, thus allowing the direct selection and editing of significant object parts.
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    A Geometric Approach for Computing the Kernel of a Polyhedron
    (The Eurographics Association, 2021) Sorgente, Tommaso; Biasotti, Silvia; Spagnuolo, Michela; Frosini, Patrizio and Giorgi, Daniela and Melzi, Simone and Rodolà, Emanuele
    We present a geometric algorithm to compute the geometric kernel of a generic polyhedron. The geometric kernel (or simply kernel) is defined as the set of points from which the whole polyhedron is visible. Whilst the computation of the kernel for a polygon has already been largely addressed in the literature, less has been done for polyhedra. Currently, the principal implementation of the kernel estimation is based on the solution of a linear programming problem. We compare against it on several examples, showing that our method is more efficient in analysing the elements of a generic tessellation. Details on the technical implementation and discussions on pros and cons of the method are also provided.
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    A Graphical Framework to Study the Correlation between Geometric Design and Simulation
    (The Eurographics Association, 2022) Cabiddu, Daniela; Patané, Giuseppe; Spagnuolo, Michela; Cabiddu, Daniela; Schneider, Teseo; Allegra, Dario; Catalano, Chiara Eva; Cherchi, Gianmarco; Scateni, Riccardo
    Partial differential equations can be solved on general polygonal and polyhedral meshes, through Polytopal Element Methods (PEMs). Unfortunately, the relation between geometry and analysis is still unknown and subject to ongoing research to identify weaker shape-regularity criteria under which PEMs can reliably work. We propose a graphical framework to support the analysis of the relation between the geometric properties of polygonal meshes and the numerical performances of PEM solvers. Our framework, namely PEMesh, allows the design of polygonal meshes that increasingly stress some geometric properties, by exploiting any external PEM solver, and supports the study of the correlation between the performances of such a solver and the geometric properties of the input mesh. Furthermore, it is highly modular, customisable, easy to use, and provides the possibility to export analysis results both as numerical values and graphical plots. The framework has a potential practical impact on ongoing and future research activities related to PEM methods, polygonal mesh generation and processing.
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    Mapping Grey-Levels on 3D Segmented Anatomical districts
    (The Eurographics Association, 2019) Paccini, Martina; Patané, Giuseppe; Spagnuolo, Michela; Agus, Marco and Corsini, Massimiliano and Pintus, Ruggero
    The study aims to perform a simple but effective integration of geometric information of segmented 3D bones' surface and density information provided by volume MRI (Magnetic Resonance Imaging). Such a representation method could support diagnosis process, biomedical simulation, computed assisted surgery and prosthesis fitting. The input consists of a volume MRI of a carpal district and the corresponding 3D surface model. The algorithm superimposes image and surface, and, once found the image voxel correspondent to each surface point, maps the grey level of the voxels identified on the segmented surface. The output is a surface mesh on which the texture, induced by the MRI, has been mapped. The approach is effective, general and applicable to different anatomical districts. Further elaboration of the results can be used to perform landmark identification or segmentation correction.
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    SGP 2022 CGF 41-5: Frontmatter
    (The Eurographics Association and John Wiley & Sons Ltd., 2022) Campen, Marcel; Spagnuolo, Michela; Campen, Marcel; Spagnuolo, Michela
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    A Survey of Indicators for Mesh Quality Assessment
    (The Eurographics Association and John Wiley & Sons Ltd., 2023) Sorgente, Tommaso; Biasotti, Silvia; Manzini, Gianmarco; Spagnuolo, Michela; Bousseau, Adrien; Theobalt, Christian
    We analyze the joint efforts made by the geometry processing and the numerical analysis communities in the last decades to define and measure the concept of ''mesh quality''. Researchers have been striving to determine how, and how much, the accuracy of a numerical simulation or a scientific computation (e.g., rendering, printing, modeling operations) depends on the particular mesh adopted to model the problem, and which geometrical features of the mesh most influence the result. The goal was to produce a mesh with good geometrical properties and the lowest possible number of elements, able to produce results in a target range of accuracy. We overview the most common quality indicators, measures, or metrics that are currently used to evaluate the goodness of a discretization and drive mesh generation or mesh coarsening/refinement processes. We analyze a number of local and global indicators, defined over two- and three-dimensional meshes with any type of elements, distinguishing between simplicial, quadrangular/hexahedral, and generic polytopal elements. We also discuss mesh optimization algorithms based on the above indicators and report common libraries for mesh analysis and quality-driven mesh optimization.